Refactoring: Set.add_m2m and Set.remove_m2m were extracted from Transaction.add_m2m and Transaction.remove_m2m
Refactoring: Set.add_m2m and Set.remove_m2m were extracted from Transaction.add_m2m and Transaction.remove_m2m

git-svn-id: cc65bc9ed7fa717314bc8890b6f123117eea230e@1486 698dff77-f410-0410-8918-cf622e150f36

ponyorm/pony,gwecho/pony,gwecho/pony,ponyorm/pony,gwecho/pony,ponyorm/pony,ponyorm/pony